Respiratory System: Functions, Organization, and Mechanics of Respiration Flashcards
What is the most critical function of the respiratory system?
provide oxygen (deliver of oxygen to the cells is a multi-step process
CO2 is an ___ waste product. Draw the equation of turning CO2 into bicarb.
acidic
CO2 + H2O → H2CO3- → HCO3- + H+
How does the respiratory system regulate blood pH?
ventilation rate affects the amount of CO2 in plasma
The respiratory systems facilitates speech via the ___ ___.
vocal cords
What are the three mechanisms used to provide microbial defense?
- epithelial secretions
- lymphoid tissue in tract
- coughing and sneezing reflexes
Epithelial secretions are ___ that traps stuff. Lymphoid tissues are found in the wall of respiratory passages and prevent pathogens from entering the ___. ___ and ___ help to expel irritants deep in respiratory tract or nasal passages.
mucus; blood; coughing; sneezing
___, an enzyme found in the endothelial cells of the lung, convert angiotensin I to angiotensin II.
ACE
How does the respiratory system defend against small blood clots that get trapped in the narrow vessels of the lungs?
they are dissolved because there is a high concentration of fibrolysins in the lungs.
T/F. Airways are the site of gas exchange between air and blood and the lungs are a series of tubes needed to exchange air between lungs and environment.
False, LUNGS are the site of gas exchange between air and blood and the AIRWAYS are a series of tubes needed to exchange air between lungs and environment.
What mechanical aids are used to vary the volume of the thoracic cavity?
skeletal muscles
The upper airway structures are ___ (inside/outside) of the thoracic cavity. List those structures?
outside
mouth/nose → pharynx → larynx→ top of trachea
The conducting zones can be found in the ___ cavity but no ___ ___ occurs.
thoracic; gas exchange
List the structures found in the conducting zone.
trachea → primary bronchi → secondary bronchi → bronchioles → terminal bronchioles
The trachea and bronchi include ___ rings and ___ glands, but the bronchioles lose ___ and ___ and add ___ ___.
cartilaginous; mucous; cartilage; glands; smooth muscle
In what structures does gas exchange occur?
Respiratory zone
respiratory bronchioles → alveolar ducts → alveolar sacs
___ bronchioles are very ___-walled and contain ___ in their walls.
Respiratory; thin; alveoli
In branching, 1 tube → ___ million tubes → ~300 ___ alveoli.
8; million
Branching creates ___ airways to maintain airflow and minimize increasing ___ to airflow.
parallel; resistance
When air is warmed and moistened, what is exchanged with the blood in airway walls?
heat and water vapor
How does the conducting zones protect against microbes?
- goblet cells secrete mucus which can trap airborne particles and pathogens
- cilia on epithelial cells move mucus upwards to the pharynx where it can be swallowed or expelled
What cells does smoking damage?
epithelial cells so an individual must cough to clear passages.
Cystic fibrosis is a disease the impairs the normal functioning of which zone?
conducting
In cystic fibrosis, a mutation in the genetic code for ___ channels reduces the amount of ___ and ___ secreted across the epithelium into the mucus.
Cl-; Na+; Cl-
What is the consequence of having less water in the mucus (due to osmosis) of cystic fibrosis patients?
their mucus, which is thick and dry, traps infectious agents, is not expelled and obstructs the airway
What regulates airflow in the respiratory zone?
bronchiolar smooth muscles that have the ability to dilate and constrict (regulated by autonomics)
Why are alveoli well-suited for optimizing gas exchange?
- high surface area for increased gas diffusion
- highly vascularized
- respiratory surface very thin
- low rate of blood flow provides time for exchange
Microbial defense is provided by pulmonary ___.
macrophages
Match the following cells of the alveoli with their function:
A. Type I
B. Type II
C. Macrophages
- secrete surfactant
- immune cells
- epithelial; gas exchange surface
A - 3
B - 1
C - 2
What is the most important factor for alveoli and pulmonary capillaries?
thinness
Alveolar sacs are ~0.5um in diameter
Distance between alveolus and capillary ~0.2um
Respiratory gases are small ___ molecules that diffuse down a “___” gradient easily through plasma ___ but less easily through body ___.
nonpolar; concentration; membranes; fluids
What are the rates of diffusion for O2 and CO2? Why are they different?
They are different due to their different solubilities
CO2 solubility = 77mmol/L
O2 solubility = 2.2mmol/L
From the air, what layers must O2 cross to enter the plasma?
air in alveolus → across apical membrane of Type I cell → through cytoplasm → across basal membrane of Type I cell → across basal lamina and underlying connective tissue → across basal membrane of endothelial cell → through cytoplasm → across apical membrane of endothelial cell → in plamsa
O2 must diffuse/move in reverse to leave blood in ___ capillaries and be delivered to ___ in tissues.
systemic; mitochondria
What are the skeletal and muscular elements that enclose the lungs inside the thoracic cage?
spinal column, ribs, breastbone (sternum), neck muscles, diaphragm and intercostal muscles
Each lungs is surrounded by a pleural sac. What are the two layers of this sac?
- parietal (outer) pleura - adheres to the underside of the thoracic wall and the top of the diaphragm
- visceral (inner) pleura - covers the outer surface of the lung
The ___ fluid surround the lungs and ___ the pleural surfaces so that they can slide over each other during breathing.
intrapleural; lubricates
How thick is the intrapleural fluid that fills the sacs? What happens to the intrapleural fluid when the thoracic cage expands or contracts?
10 - 20um thick
subject to pressure changes when thoracic cage expands or contracts
___ is required to bring freshly oxygenated air into the lungs and ___ relies on pressure differences between the air in the lungs and the air outside of the lungs.
Ventilation; ventilation
Define airflow.
a function of the pressure gradient and the resistance to flow within the airways
F = change in P / R or F = (Palv - Patm) / R
Patm = pressure at ___ level = ___mm Hg or ___ atm
sea; 760; 1 (for this class Patm = 0
What happens if Palv is less than Patm?
If Patm is = 0, then Palv is negative and air flows into lungs (inspiration)
T/F. If Palv is greater than Patm then air flow out of lungs (expiration).
True.
Alveolar pressure changes in response to changing the volume of the lungs according to Boyle’s law. What is Boyle’s law?
P1V1 = P2V2
What three pressures relate to ventilation?
- alveolar (Palv) - air pressure w/in alveoli
- Intrapleural (Pip) - pressure of fluid in the intrapleural space
- transpulmonary (Ptp)
How do you determine the transpulmonary pressure?
Ptp = Palv - Pip
During inspiration, the ___ contracts and lowers the floor of the cavity to ___ volume. The ___ intercostal muscles contract and raise the ribcage to ___ the volume.
diaphragm; increase; external; increase
During expiration, the ___ relaxes and raises the floor of the cavity to ___ volume and ___ intercostals relax to lower the ribcage and ___ volume.
diaphragm; reduces; external; reduces
As the volume of the thoracic cavity expands during inspiration, what happens to Pip, Ptp and Palv?
Pip decreases and Ptp becomes more positive as a result and the lungs expand (increase vol of alveoli). As this occurs, Palv becomes more negative compared to Patm and air flows inward.
T/F. Between breaths, Patm is negative and Palv is greater causing one to exhale.
False, during breaths, Patm is = 0; Palv = Patm between breaths (so NO air is moving)
The ___ tend to recoil inward and the ___ ___ tends to recoil outward.
lungs; chest wall
T/F. Between breaths, Pip is always subatmospheric.
True.
What muscles are involved in forced inspiration? expiration?
forced inspiration:
- SCM
- pectoral ms
- scapular ms
forced expiration:
- abdominal ms
- latissimus dorsi
- internal intercostal ms
When the diaphragm and inspiratory intercostals contract, the thorax ___ and ___ becomes more subatmospheric. There is an ___ in transpulmonary pressure and the lungs ___. Palv becomes ___ and air flows ___ the alveoli.
expands; Pip; increase; expand; subatmospheric; into
When the diaphragm and inspiratory intercostals stop contracting, the chest wall ___ and ___ moves back toward its preinspiratory value. ___ pressure moves back also and the lungs ___ toward their preinspiratory size. Air in the alveoli becomes ___ and Palv becomes ___ than Patm so air flows ___ of the lungs.
recoils; Pip; Transpulmonary; recoil; compressed; greater; out
A ___ occurs when the lung (actually the ___ ___) is punctured. ___ air enters the intrapleural space and the intrapleural pressure increases to ___. Now Pip is equal to Patm. The pressure acting to hold the lung open is thus eliminated and the lung ___. At the same time the chest wall moves ___ because the elastic recoil is no longer opposed.
Pneumothorax; pleural sac; Atmospheric; zero; collapses; outward
